The present invention relates to a gas sampling device, and, more particularly, to an atmospheric gas sampler with a multi-port valve which allows for multiple, sequential sampling of air through a plurality of sample tubes mounted in corresponding ports.
Small and lightweight atmospheric gas samplers are useful in conducting various environmental, meteorological and atmospheric tests. Whether for detecting hazardous contaminants or studying the atmosphere, gas samplers are essential for collecting or detecting various gases, aerosols and other particulates in the atmosphere. Typically, sampling is conducted by drawing air through a sample tube containing certain adsorbents which trap the target gases or particulates. These adsorbed gases or particulates are then later analyzed in the laboratory. As these studies have become more complex, there has been an increasing need, not only to take large numbers of samples, but also to take samples at various locations, times, and altitudes. Accordingly, there is a need for samplers which can take numerous gas samples efficiently and accurately, and whose functions can be automated.
The need for a compact, lightweight and efficient gas sampler is especially important in various atmospheric and meteorological studies. In atmospheric transport studies, a tracer gas, in the form of a perfluorocarbon, is released in predetermined amounts from various preselected positions. The tracer gas is then collected by gas samplers deployed at various locations and analyzed to examine atmospheric transport properties. In gas dispersion studies, certain gases or aerosols are selectively sampled at various locations and altitudes to determine their concentrations and to characterize their vertical structure or profile. These and other related experiments have been used to validate models describing atmospheric transport and dispersion of pollutants.
To perform such atmospheric experiments, gas samplers are normally attached to balloon tetherlines and lofted to various altitudes to take samples. In such applications, the gas samplers must be small and lightweight so that several samplers can be taken up together. Ideally, each gas sampler should accommodate multiple sample tubes so that many air samples can be taken at one lofting. Previously, however, gas samplers usually contained only a single adsorbent sample tube such that the balloon had to be hauled down after each sampling. Some gas samplers have the capability to take multiple samples, but these were typically heavy, complicated and not conducive to automated operation. What is needed is a simple, lightweight gas sampler which can take multiple samples and whose operation can be fully automated.
In view of the foregoing, the general object of this invention is to provide an atmospheric gas sampler with a multi-port valve which allows successive sampling of air through a plurality of sample tubes mounted in corresponding ports.
Another object of this invention is to provide a self-contained and fully automated gas sampler including unique electrical switches that provide reliable signals to an electrical control system that a port has been opened or closed.
Yet another object of this invention is to provide a gas sampler with a nozzle or check valve that prevents back-flow of air into the sample tubes.
Additional objects, advantages and novel features of the invention will become apparent to those skilled in the art upon examination of the following and by practice of the invention.